Search results

  1. catrafter

    Marantz 250 restoration query

    Be Aware, one side is upside down from the other. Tom
  2. catrafter

    Marantz Quadradial Units

    To me, Quadradial means 4 channel and then 2 channels (bridged) at increased power. Tom
  3. catrafter

    Help with a 2270 Phono Amp Board (Tantalum Caps)

    Ecluser's excellent post on the subject of 2270 bias is in this thread. Tom
  4. catrafter

    Marantz 250 restoration query

    I have seen that diode both under and on top of Q507. There is also a bias network mounted on the rear of the heat sink on some models. Tom
  5. catrafter

    Marantz 1152 question

    https://audiokarma.org/forums/index.php?threads/marantz-control-cross-reference-spreadsheet.923978/
  6. catrafter

    Marantz 250 restoration query

    Perhaps 1N270 would work, you may have to replace all four in that bridge, CR404, CR405, CR407 and CR408 Tom
  7. catrafter

    Marantz 250 restoration query

    If the MM8005 are in the bases of the meter drivers and the bridge rectifier for the meters, I doubt IN4007 will work.
  8. catrafter

    Marantz 250 restoration query

    The black ones look like regular rectifier diodes, 1N4007 should be OK. The two next to the big resistors are Zener diodes, 13V 1W (1N9648) IIRC. The others? You will probably have to find someone who knows more about it than I. Tom
  9. catrafter

    Final Testing Process - How do you test your finished Marantz projects?

    It takes some specialized test gear (recently calibrated) to ensure that the gear meets it's published specs. If you are doing work for yourself you can do as you please. Tom
  10. catrafter

    Marantz 250 restoration query

    460-1009 crosses to an NTE177, a common rectifier, 1N4009 might work A photo or schematic might help. Tom
  11. catrafter

    2010 radio on the fritz

    Clean the tuner before you do anything else. Tom
  12. catrafter

    2015 volume and power lower in right channel

    I'd fix the problem first. Tom
  13. catrafter

    Marantz 1152DC Offset

    Check the +/- 45VDC power supply for drift. Tom
  14. catrafter

    Speaker Terminals

    Stock may preserve the value, but they are prone to breakage. Tom
  15. catrafter

    Help with marantz 2245

    Everything I know about 2270 (2245) bias is in this thread. Tom
  16. catrafter

    Still looking for contact with Bob Speece (He's STILL got my gear!)

    That's great news, I was afraid he had 'gone under'. If you talk with him again, ask him to call me. I miss chatting with him. Tom
  17. catrafter

    Marantz 2245 left amp board P750 blown-up. Need help or suggestions.

    Aavid 323005B00000G are widely available. YMMV Tom
  18. catrafter

    Marantz 250 restoration query

    If they are not present, install some. YMMV Tom
  19. catrafter

    Of flyback diodes and bypass caps

    Always both: The fly back diodes for safety the bypass caps just because large filters can have a small amount of inductance. YMMV Tom
  20. catrafter

    Marantz 250M needs new RCA jacks

    I think you will want some insulated (isolated) panel mount types that fit the rear panel holes without modification. I don't have an 'M' here at the moment to measure. They need to be isolated from the metal chassis as they have their own shield connection. Tom
  21. catrafter

    Yet another butchered 250

    IMHO, negative feedback covers up 'visible' crossover distortion in most cases. Tom
  22. catrafter

    How many WIMA films can you stuff on a Tone Board?

    I like to replace any electrolytic capacitors in the direct audio signal path with film types. What the 'direct audio signal path' is exactly is up for debate. Tom
  23. catrafter

    Diodes

    I always replace epoxy 'gob' diodes with glass types Tom
  24. catrafter

    Marantz 250 Transistor Subs?

    No, that was just general information, those are what I call 'pre-drivers' as they are the driver for the driver transistors.. I will send you four new ON-Semi output transistors with theTO-66 drivers. Tom
  25. catrafter

    4220 with a low left channel

    The circuit board that the balance controls are mounted on is frequently a problem on these. The 'griplets' or rivets that connect the traces on each side of the circuit board loose contact. Tom
Back
Top Bottom